“When he arrived, [he] was already in cardiac arrest. He was put under resuscitation treatment for 40 minutes, but the emergency staff failed to restart his heart, and at 23:00, he was pronounced deceased," said Modini, who did not personally treat the actor, via telephone, adding that "he could have been deceased on arrival since he was already in cardiac arrest.”

“Last night at approximately 10 p.m., James Gandolfini, while on vacation in Rome, experienced a medical emergency," Kobold said in a prepared statement. "The hotel notified the emergency crews, who responded and first aid was administered before Mr. Gandolfini was taken to a hospital, where he died of an apparent heart attack. Our prayers and condolences go to Mr Gandolfini’s family and friends. We ask you all to please respect the family’s privacy at this difficult time.”

Kobold also said that Gandolfini was discovered in his room by a family member, though he did not elaborate further. In a statement to USA Today, hotel spokesperson Laura Conti said it was Gandolfini’s son Michael, 13, who initially called reception for help.

Gandolfini was traveling with a group that reportedly included wife Deborah Lin and their 9-month-old daughter, Liliana, as well as other friends and family members.

His assistant, Tom Richardson, also told USA Today that the group had just returned to the hotel after “a marvelous day together” when Gandolfini went to the bathroom. “That is where something happened,” he said. "His sister said he was still alive when the ambulance took him away."

According to Rome's Il Messaggero newspaper, Gandolfini arrived at the hotel Wednesday morning showing no signs of illness, and dined inside the hotel that evening. He signed autographs and appeared to be in good spirits.

Gandolfini was in Italy to attend the Taormina Film Festival in Sicily, where he was to have been honored with the Taormina City Prize at the event’s closing ceremony this weekend.

James Gandolfini, who played Tony Soprano on HBO's "The Sopranos," has died of a possible heart attack, HBO has confirmed. Here's a look back at his career. RELATED PHOTOS: Life in pictures | Celebrities react on Twitter

Critic's notebook: As Tony Soprano in HBO's mob drama, the actor found his greatest role. It's too bad the movies didn't know how to make the most of his prodigious talents as a leading man the way 'The Sopranos' did.

James Gandolfini, the most important actor in the most influential television series of the last decade and a half, died suddenly Wednesday, in Italy. He was only 51, and though he had been a busy working actor -- in film and onstage as well as on TV -- for two decades, and had (with writer David...